The Wisdom Door Knows You

The Wisdom Door is a prototype created by students at Duke University in Durham, North Carolina. We're all familiar with key-card doors and other devices that require a special password. The Wisdom Door, however, uses specific biometric information to decide who enters.

This sensor-intensive door doesn't make you stop and identify yourself. Nine different sensors work together to find enough information for identification.

At the top of the door, an ultrasonic sensor beams a signal downward. Bouncing off the top of the head, it comes back, and provides the height of the person.

Four infrared sensors mounted in the door jambs provide a measurement of girth (side-to-side and front-to-back). When a person walks through, the beams are broken at specific points that can be determined. The same sensors find the delay involved in first encountering the infrared sensor beams, and then passing through the door.

Finally, four load sensors in a panel in the floor determine weight. Over time, the system can build up a database of characteristics that identify individuals.

Obviously, this prototype has limits; what if a woman wears high heels, or if a guy wears an especially bulky coat.

Science fiction writer Philip K. Dick had a better idea. In his 1965 story The Zap Gun, one of his characters improves security with a cephalic pattern door:

The doors of Mr. Lars, Incorporated, shut, tuned as they were to his own cephalic pattern.
(Read more about Dick's cephalic pattern door)

The "cephalic pattern" refers to the unique patterns revealed in the electrical signals of a person's brain. Dick was fascinated by this idea; see also his Cephalochromoscope (Cephscope), a fun consumer device.